【発明の詳細な説明】[Detailed description of the invention]
産業上の利用分野
本発明はCdS／CdTe系太陽電池に使用する焼
結膜の製造方法に関するものである。
従来例の構成とその問題点
焼結膜の製造方法の１つとして半導体粉末を用
いて印刷ペーストを作製し、このペーストをスク
リーン印刷法で基板上に塗布後、乾燥、焼成を行
なうことにより製造する方法がある。この製造方
法では半導体粉末を焼成中に結晶成長させるため
に印刷ペーストの中に融剤を添加している。この
様な融剤を用いた半導体膜の焼成は、これまで主
に高抵抗な光導電素子の製造方法として用いられ
てきた。その場合の焼成方法としては、半導体膜
を塗布した基板をそのままの状態で焼成炉に入れ
るか、密閉した容器中に入れて焼成炉に入れてい
た。
ところが特公昭52−25305号公報で、同一基板
上に多数個の高抵抗な光導電素子を製造する場合
にそれらの光導電素子の特性を揃えるために有孔
蓋付きの焼成容器が使用することが開示されてい
る。
一方、太陽電池用の半導体膜としては、低抵抗
であることが必要である。ところがスクリーン印
刷法による基板への半導体層の塗布とその後の焼
成による半導体焼結膜の製造方法では、これまで
太陽電池用の低抵抗な膜の製造は、前述の基板を
そのままの状態で焼成炉に入れるか、密閉した容
器中に入れて焼成していた。しかし、いずれの場
合も低抵抗な半導体膜を得ることが困難であり、
融剤を用いた焼成膜により製造された太陽電池は
十分な出力特性を示さず、これまで実用化されて
いない。
以下、従来例の欠点を詳細に説明する。太陽電
池用半導体材料として−族化合物半導体は有
望であり、その薄膜太陽電池の開発が活発に行な
われている。その場合、CdS，CdSeなどの焼結
膜を得るために、融剤としてCdCl2が用いられ
る。しかし、太陽電池用の半導体膜としては低抵
抗であることが必要であり、またヘテロ接合太陽
電池の窓材料として使用される場合には、光の透
過率が高いことが大切であるが、このような要求
を満す焼結膜を得ることはCdCl2などの融剤を用
いた製造方法ではこれまで困難であつた。その理
由をCdS膜の作製を例にとつて説明する。
CdS焼結膜を得るためには融剤としてCdCl2が
用いられるが、この融剤の働きが焼結膜に与える
影響は非常に大きい。例えば、CdS膜を塗布した
基板を密閉容器中に入れベルト式の焼成炉中で焼
成を行なうと、まず共晶点以上（522℃）の温度
でCdCl2融液の中にCdSが溶け込み、その後の温
度上昇でCdCl2が蒸発しだす。
その結果、過飽和融液中でのCdSの結晶成長が
行なわれ、CdS焼結膜が得られる。ところが、密
閉容器中ではこのCdCl2の容器外への蒸発が行な
われないため、十分に結晶成長し透過率の高い膜
となるが、焼成中にCdCl2のCl-が多量に膜中に
残存しCdS膜の抵抗が高くなつてしまい、太陽電
池用の焼成膜としては使用できない。
また、基板をそのままベルト炉中に入れて焼成
すると、焼成中にCdCl2融剤が瞬時に蒸発してし
まうため、CdSの結晶成長が十分に行なわれず、
粒径の小さいCdS膜が得られる。ところがこの様
な膜では膜中に残存するCl-は少ないという結果
となるが、結晶粒の成長が不十分であるため透過
率の低い高抵抗なCdS膜が得られることになり、
やはり太陽電池用の焼結膜としは使用できない。
そこで焼成容器の蓋の部分に穴を開け、その穴
を通してCdCl2融剤蒸気の蒸発のコントロールを
行なえば結晶成長を十分に行なわれ、膜中に残存
するCl-量の少ない低抵抗な焼結膜が得られる可
能性があるため、焼成容器の蓋の穴の径とその個
数を変えて、焼成中のCdCl2融剤蒸発速度の制御
を行なう方法を検討した。その結果、焼成容器に
入れる基板面積と焼成容器の蓋の穴の面積とを調
整することにより、すなわち焼成容器の蓋の穴面
積を、従来特公昭52−25305号公報により提案さ
れていたような高抵抗の光導電素子を製造する方
法におけるよりもいちじるしく狭めることによ
り、低抵抗な焼結膜を再現性よく容易に得られる
ことがわかつた。
発明の目的
本発明は、融剤を用いて製造した半導体薄膜よ
りなる太陽電池の製造において、低抵抗な半導体
薄膜の製造方法を提供することを目的とするもの
である。即ち、上述の特公昭52−25305号公報で、
同一基板上の複数個の高抵抗光導電素子の光導電
特性を揃えるために使用された有孔蓋つきのボー
トに基板を入れて焼成する製造方法を改良するこ
とにより低抵抗な半導体薄膜を得ることを目的と
する。
発明の構成
本発明の焼結膜の製造法は、複数個の開孔を有
する焼成容器内で被焼結膜を焼成する焼結膜の製
造において、前記複数個の開孔の面積の総和を焼
成される被焼結膜面積の0.4％から2.0％にするも
のである。
実施例の説明
以下、本発明の実施例を図面にもとづいて説明
する。第１図、第２図は本発明を実施するために
用いられた焼成容器のボート部分と蓋の部分図で
あり第３図は本発明の実施例の方法により製造さ
れた太陽電池の構造図である。
CdS粉末100gに対してCdCl210gを添加し、粘
度調整節のためプロピレングリコールを適量混合
してCdS印刷ペーストを作製する。10cm×10cmの
ガラス基板上にスクリーン印刷機を用いてこのペ
ーストを全面印刷した後、100℃の乾燥機で１時
間乾燥する。乾燥後、基板をアルミナ製の焼成ボ
ート１の中に入れ、その上にアルミナ製の有孔蓋
２を置く。焼成ボートの深さは３mmで、ボートの
大きさは内径10.2cm×10.2cmである。この焼成ボ
ートを690℃の温度に保たれたベルト式焼成炉に
入れ約60〜90分間焼成する。焼成の穴３の効果を
調べるため、穴の径と数を変えたアルミナ製の蓋
を作製し、前述のCdS基板の焼成を行なつた。こ
れら約30μ厚のCdS焼結膜を用い、太陽電池とし
ての特性を評価した。太陽電池は第３図の構造で
次の様にして作製した。Cd粉末とTe粉末100gに
CdCl2粉末0.5gを添加し、適量のプロピレングリ
コールと混合することによりCdTe印刷ペースト
を作製する。この印刷ペーストをガラス基板４上
のCdS焼結膜５上にスクリーン印刷法にて塗布し
乾燥する、この基板を前述のアルミナ製の焼成容
器中に入れベルト式焼成炉の620℃の温度で約１
時間焼成する。この時使用するアルミナ製の焼成
容器はすべて同一であり、蓋の穴の面積は、１mm
の穴を181個開けたもので穴の総和面積は約1.42
cm2である。
この様にして得られたCdTe膜６上にカーボン
ペーストを用いてカーボン層を印刷し、400℃で
約30分間ベルト式焼成炉で焼成することによりカ
ーボン電極７を形成する。このカーボン電極上に
Ag電極８とCdS膜上にAg−In電極９をそれぞれ
スクリーン印刷とその後の熱処理で形成し、Ag
電極とAg−In電極よりリード線１０を取り出し
CdS／CdTe太陽電池を作製した。この太陽電池
にAM1.5、100mw／cm2のソーラシミユレターか
らの光を照射しエネルギー変換効率（真性変換効
率）を測定した。第１表に、CdS焼結膜の焼成時
の焼成容器の蓋の穴の総和面積を変えた場合の各
CdS膜の諸特性とこれらのCdS／CdTe太陽電池
の特性を示した。
INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing a sintered film used in a CdS/CdTe solar cell. Structure of conventional example and its problems One method for manufacturing a sintered film is to create a printing paste using semiconductor powder, apply this paste onto a substrate using a screen printing method, and then dry and bake it. There is a way. In this manufacturing method, a flux is added to the printing paste in order to cause crystal growth of the semiconductor powder during firing. Sintering of a semiconductor film using such a flux has hitherto been mainly used as a method for manufacturing high-resistance photoconductive elements. In this case, the firing method is to put the substrate coated with the semiconductor film into a firing furnace as it is, or to put it in a sealed container and put it into the firing furnace. However, Japanese Patent Publication No. 52-25305 discloses that when manufacturing a large number of high-resistance photoconductive elements on the same substrate, a firing container with a perforated lid is used to make the characteristics of the photoconductive elements uniform. is disclosed. On the other hand, a semiconductor film for solar cells needs to have low resistance. However, with the method of manufacturing a sintered semiconductor film by applying a semiconductor layer to a substrate using screen printing and subsequent firing, it has been difficult to manufacture a low-resistance film for solar cells by leaving the substrate as is in a firing furnace. It was then baked in a sealed container. However, in either case, it is difficult to obtain a low-resistance semiconductor film;
Solar cells manufactured by firing films using flux do not exhibit sufficient output characteristics and have not been put into practical use so far. Hereinafter, the drawbacks of the conventional example will be explained in detail. BACKGROUND ART - Group compound semiconductors are promising as semiconductor materials for solar cells, and thin film solar cells using them are actively being developed. In that case, CdCl 2 is used as a flux to obtain a sintered film of CdS, CdSe, etc. However, as a semiconductor film for solar cells, it is necessary to have low resistance, and when used as a window material for heterojunction solar cells, it is important to have high light transmittance. Until now, it has been difficult to obtain a sintered film that satisfies these requirements using a manufacturing method that uses a flux such as CdCl 2 . The reason for this will be explained using the production of a CdS film as an example. CdCl 2 is used as a flux to obtain a CdS sintered film, and the effect of this flux on the sintered film is extremely large. For example, when a substrate coated with a CdS film is placed in a closed container and fired in a belt-type firing furnace, CdS first dissolves into the CdCl 2 melt at a temperature above the eutectic point (522°C), and then As the temperature increases, CdCl 2 begins to evaporate. As a result, CdS crystal growth occurs in the supersaturated melt, and a CdS sintered film is obtained. However, in a closed container, this CdCl 2 does not evaporate outside the container, so crystals grow sufficiently and a film with high transmittance is obtained, but a large amount of Cl - from CdCl 2 remains in the film during firing. However, the resistance of the CdS film becomes high, and it cannot be used as a fired film for solar cells. Additionally, if the substrate is placed in a belt furnace and fired, the CdCl 2 flux will instantly evaporate during firing, resulting in insufficient CdS crystal growth.
A CdS film with small particle size can be obtained. However, in such a film, although the amount of Cl - remaining in the film is small, the growth of crystal grains is insufficient, resulting in a high-resistance CdS film with low transmittance.
After all, it cannot be used as a sintered film for solar cells. Therefore, if a hole is made in the lid of the firing container and the evaporation of the CdCl 2 flux is controlled through the hole, sufficient crystal growth will occur, resulting in a low-resistance sintered film with a small amount of Cl remaining in the film. Therefore, we investigated a method of controlling the evaporation rate of CdCl 2 flux during firing by changing the diameter and number of holes in the lid of the firing vessel. As a result, by adjusting the area of the substrate to be placed in the firing container and the area of the hole in the lid of the firing container, the area of the hole in the lid of the firing container can be adjusted as proposed in Japanese Patent Publication No. 52-25305. It has been found that a low resistance sintered film can be easily obtained with good reproducibility by significantly narrowing the area compared to the method for manufacturing a high resistance photoconductive element. OBJECTS OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor thin film with low resistance in manufacturing a solar cell made of a semiconductor thin film manufactured using a flux. That is, in the above-mentioned Japanese Patent Publication No. 52-25305,
Obtaining a low-resistance semiconductor thin film by improving the manufacturing method of placing a substrate in a boat with a perforated lid and firing it, which was used to equalize the photoconductive properties of multiple high-resistance photoconductive elements on the same substrate. With the goal. Composition of the Invention The method for manufacturing a sintered film of the present invention is such that in manufacturing a sintered film in which a film to be sintered is fired in a firing container having a plurality of openings, the total area of the plurality of openings is fired. The amount is increased from 0.4% to 2.0% of the area of the film to be sintered. DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on the drawings. Figures 1 and 2 are partial views of the boat and lid of the firing container used to carry out the present invention, and Figure 3 is a structural diagram of a solar cell manufactured by the method of the embodiment of the present invention. It is. A CdS printing paste is prepared by adding 10 g of CdCl 2 to 100 g of CdS powder and mixing an appropriate amount of propylene glycol to adjust the viscosity. This paste was printed on the entire surface of a 10 cm x 10 cm glass substrate using a screen printer, and then dried in a dryer at 100°C for 1 hour. After drying, the substrate is placed in a firing boat 1 made of alumina, and a perforated lid 2 made of alumina is placed on top of it. The depth of the firing boat was 3 mm, and the size of the boat was 10.2 cm in inner diameter x 10.2 cm. This firing boat is placed in a belt-type firing furnace maintained at a temperature of 690°C and fired for approximately 60 to 90 minutes. In order to investigate the effect of holes 3 during firing, alumina lids with different hole diameters and numbers were fabricated, and the CdS substrates described above were fired. Using these approximately 30μ thick CdS sintered films, we evaluated their properties as solar cells. A solar cell having the structure shown in FIG. 3 was manufactured in the following manner. 100g of Cd powder and Te powder
Make CdTe printing paste by adding 0.5 g of CdCl2 powder and mixing with appropriate amount of propylene glycol. This printing paste is applied onto the CdS sintered film 5 on the glass substrate 4 by a screen printing method and dried.The substrate is placed in the alumina firing container mentioned above and heated at a temperature of 620°C in a belt type firing furnace for about 1 hour.
Bake for an hour. The alumina firing containers used at this time are all the same, and the area of the hole in the lid is 1 mm.
181 holes are drilled, and the total area of the holes is approximately 1.42.
cm2 . A carbon layer is printed using carbon paste on the CdTe film 6 obtained in this way, and the carbon electrode 7 is formed by firing it in a belt-type firing furnace at 400° C. for about 30 minutes. on this carbon electrode
An Ag-In electrode 9 is formed on the Ag electrode 8 and the CdS film by screen printing and subsequent heat treatment, and the Ag
Take out lead wire 10 from the electrode and Ag-In electrode.
A CdS/CdTe solar cell was fabricated. This solar cell was irradiated with light from a solar simulator of AM1.5 and 100 mw/cm 2 to measure energy conversion efficiency (intrinsic conversion efficiency). Table 1 shows the effects of changing the total area of the holes in the lid of the firing container during firing of the CdS sintered film.
The various properties of CdS films and the properties of these CdS/CdTe solar cells are shown.
【表】
第１表より明らかなように蓋穴の総和面積の小
さい場合はCdS膜の面抵抗が高く膜中に残存する
Cl-量も多い。ところが穴の総和面積の増加につ
れ面抵抗も減少し、穴の総和面積が0.4〜2.0cm2の
範囲でほぼ一定の70〜180Ω／□の面抵抗を示す
様になり、低抵抗のCdS膜が得られている。とこ
ろが、更に穴総和面積を増加させるとCdS膜の面
抵抗が徐々に増加するとともに結晶粒径も減少し
だす。この結晶粒径の減少は膜抵抗の増大ととも
に光の透過率の減少をも引き起こす。
以上の様なCdS膜の特徴が太陽電池の変換効率
に与える影響はどうかとみると穴の総和面積0.3
cm2以下の場合は変換効率が悪い。この原因はCdS
膜の面抵抗の高さとともに第４図の分光感度特性
の曲線１１のような短波長側での感度の低下によ
る原因が大きい。これはCdS膜中に残存するCl-
量によるもので、この残存量が多ければ多いほど
太陽電池を作製した場合、CdS膜とCdTe膜との
界面にCl-の働きで厚いCdSXTe1-X層が形成され、
この層による光吸収のため短波長側の感度が低下
することがわかつた。したがつてCdS膜中の残存
Cl-量は少ないことが望ましい。穴の総和面積が
0.4cm2以上の場合のCdS膜を用いて太陽電池を作
製した場合の分光感度特性は、曲線１２のごとく
短波長側の感度はCdS膜の基礎吸収端（0.52μm）
で決まり残存Cl-量による特性への影響はみられ
ない。穴の総和面積0.4cm2から2.0cm2の範囲の太陽
電池はCdS膜の面抵抗も低く、結晶粒径も25〜
35μmと大きく光の透過率も高いため真性変換効
率は7.0〜8.5％と高く安定である。ところが穴の
総和面積3.1cm2以上の場合、残存Cl-量は穴の総和
面積0.4〜2.0cm2の場合と同様低く、短波長側感度
の低下はないが、CdS膜の面抵抗が大きくなりは
じめることと結晶粒径の減少による光の透過率の
低下のため真性変換効率は穴面積の増加により低
下しだし7.0％以上のものは得られなかつた。
以上の様にCdS膜焼成時のアルミナ製焼成容器
の蓋の穴の総和面積の変化により、CdS膜および
それを用いて作製したCdS／CdTe太陽電池の特
性に明らかに変化のあることがわかつた。即ち、
穴の総和面積が小さい場合は、CdS膜に残存する
Cl-量が光起電力特性に悪い影響を与え穴の総和
面積の大きい場合は、CdS膜の結晶粒径が十分成
長せず、膜の高抵抗化と光の透過率の低下を生じ
変換効率の高い太陽電池が得られなかつた。太陽
電池用のCdS膜として十分に低抵抗で光の透過率
高い特性を示す膜は、焼成容器の蓋穴の面積総和
が0.4〜2.0cm2の範囲の場合に得られ、CdS／CdTe
太陽電池の変換効率が7.0％以上と高く実用上問
題はない。
また、CdS印刷ペーストの作製時、CdCl2粉末
の添加量をCdS粉末100gに対して６〜12gと変え
て同様の実験を行なつたが第１表の傾向とほとん
ど同じであり蓋穴の総和面積が0.4〜2.0cm2の場合
に、CdS膜の抵抗が低く太陽電池の変換効率も大
きかつた。また、アルミナ製蓋穴の穴は同じ大き
さの穴を左右、上下対称で均一に配置した場合ほ
どCdS膜の膜抵抗の均一なものが得られ、その抵
抗値のバラツキは10×10cm2基板で±10％以内であ
つた。このCdS膜と接合を形成するCdTe膜の焼
成時においても同様の傾向があり、焼成用のアル
ミナ製蓋穴の総和面積が上記の範囲の場合に最も
よい接合特性を示し太陽電池の変換効率も7.0〜
8.5％と高かつた。
さらに、太陽電池用の窓材料として用いられる
ZnXCd1-XＳ膜（Ｘ＝0.1）の場合でも、融剤とし
てCdCl2を用いた場合には同様の結果が得られ
た。蓋穴の総和面積が0.4〜2.0cm2の場合にZnX
Cd1-XＳ焼成膜の抵抗が最も低く300〜600Ω／□
となつた。
この様なアルミナ製の焼成容器は、材質として
は、石英ガラス、磁器のような耐薬品、耐熱性の
あるものであればどのようなものでも利用できる
し、蓋にあける穴も、穴でなくてもCdCl2が通過
できるような部分があれば、同様の効果が得られ
る。
発明の効果
本発明の方法によれば、融剤を用いた焼結膜の
製造時に有孔蓋付の焼成容器を用い、その蓋の穴
面積を調整するだけで低抵抗の焼結膜が安定に得
られる。すなわちこれまでCdS／CdTe系太陽電
池用の低抵抗な焼結膜を得ることは困難であつた
が、本発明の方法によれば焼成時に蓋穴の総和面
積が焼結膜面積の0.4〜2.0％ある焼成容器さえ用
いれば容易に低抵抗な膜が得られ、その工業上の
利点は大きい。また安価で、実用的な太陽電池を
容易に大量生産することができる製造方法である
スクリーン印刷ベルト炉焼成法の特徴を失うこと
なく、変換効率の高い太陽電池を再現性よく製造
することができる利点もある。[Table] As is clear from Table 1, when the total area of the cover holes is small, the sheet resistance of the CdS film is high and it remains in the film.
The amount of Cl - is also high. However, as the total area of the holes increases, the sheet resistance decreases, and when the total area of the holes is in the range of 0.4 to 2.0 cm2 , the sheet resistance is almost constant at 70 to 180 Ω/□, indicating that the low resistance CdS film It has been obtained. However, when the total hole area is further increased, the sheet resistance of the CdS film gradually increases and the crystal grain size begins to decrease. This decrease in crystal grain size causes an increase in film resistance and a decrease in light transmittance. Looking at the effects of the above characteristics of the CdS film on the conversion efficiency of solar cells, the total area of the holes is 0.3
If it is less than cm2 , the conversion efficiency is poor. The cause of this is CdS
This is largely due to the decrease in sensitivity on the short wavelength side, as shown by curve 11 of the spectral sensitivity characteristic in FIG. 4, as well as the high sheet resistance of the film. This is due to the Cl - remaining in the CdS film.
The larger the remaining amount, the more a thick CdS
It was found that sensitivity on the short wavelength side decreased due to light absorption by this layer. Therefore, the residual in the CdS film
It is desirable that the amount of Cl - is small. The total area of the holes is
The spectral sensitivity characteristics when a solar cell is fabricated using a CdS film with a thickness of 0.4 cm 2 or more are as shown in curve 12, where the sensitivity on the short wavelength side is at the fundamental absorption edge of the CdS film (0.52 μm).
The characteristics are not affected by the amount of residual Cl - . Solar cells with a total area of holes in the range of 0.4 cm 2 to 2.0 cm 2 have a low sheet resistance of the CdS film and a crystal grain size of 25 to 25 cm.
Because it is large at 35 μm and has high light transmittance, the intrinsic conversion efficiency is high and stable at 7.0 to 8.5%. However, when the total area of the holes is 3.1 cm 2 or more, the amount of residual Cl - is as low as when the total area of the holes is 0.4 to 2.0 cm 2 , and although there is no decrease in short wavelength sensitivity, the sheet resistance of the CdS film increases. Due to the decrease in light transmittance due to the decrease in the crystal grain size and the decrease in the crystal grain size, the intrinsic conversion efficiency began to decrease as the hole area increased, and a value higher than 7.0% could not be obtained. As described above, it was found that changes in the total area of the holes in the lid of the alumina firing container during CdS film firing clearly change the characteristics of the CdS film and the CdS/CdTe solar cells fabricated using it. . That is,
If the total area of holes is small, they remain in the CdS film.
If the amount of Cl - has a negative effect on the photovoltaic characteristics and the total area of the holes is large, the crystal grain size of the CdS film will not grow sufficiently, resulting in a high resistance of the film and a decrease in light transmittance, resulting in a decrease in conversion efficiency. However, it was not possible to obtain a solar cell with high energy efficiency. A film with sufficiently low resistance and high light transmittance as a CdS film for solar cells can be obtained when the total area of the lid holes of the firing container is in the range of 0.4 to 2.0 cm2 .
The conversion efficiency of the solar cells is high at over 7.0%, so there is no problem in practical use. In addition, when producing CdS printing paste, we conducted a similar experiment by changing the amount of CdCl 2 powder added from 6 to 12 g per 100 g of CdS powder, but the trend was almost the same as that shown in Table 1, and the total number of lid holes was When the area was 0.4 to 2.0 cm 2 , the resistance of the CdS film was low and the conversion efficiency of the solar cell was high. In addition, when the holes of the alumina lid hole are the same size and are evenly arranged horizontally and vertically symmetrically, the film resistance of the CdS film becomes more uniform, and the variation in resistance value is reduced to 10 × 10 cm 2 substrates. It was within ±10%. There is a similar tendency when firing the CdTe film that forms a bond with this CdS film, and when the total area of the alumina lid holes for firing is within the above range, the best bonding characteristics are exhibited and the conversion efficiency of the solar cell is also improved. 7.0～
It was high at 8.5%. Furthermore, it is used as a window material for solar cells.
Similar results were obtained for the Zn x Cd 1-x S film (X = 0.1) when CdCl 2 was used as the fluxing agent. Zn _
Cd 1-X S fired film has the lowest resistance of 300-600Ω/□
It became. Such alumina firing containers can be made of any material that is chemically and heat resistant, such as quartz glass or porcelain, and the hole in the lid is not just a hole. A similar effect can be obtained if there is a part through which CdCl 2 can pass. Effects of the Invention According to the method of the present invention, a sintered film with low resistance can be stably obtained by simply adjusting the hole area of the lid by using a firing container with a perforated lid when producing a sintered film using a flux. It will be done. In other words, until now it has been difficult to obtain a low-resistance sintered film for CdS/CdTe solar cells, but according to the method of the present invention, the total area of the lid holes during firing is 0.4 to 2.0% of the sintered film area. A low-resistance film can be easily obtained by using only a firing container, and its industrial advantages are great. In addition, solar cells with high conversion efficiency can be manufactured with good reproducibility without losing the characteristics of the screen printing belt furnace firing method, which is a manufacturing method that allows easy mass production of inexpensive and practical solar cells. There are also advantages.
【図面の簡単な説明】[Brief explanation of drawings]
第１図ａは本発明の焼結膜の製造方法に使用す
る焼成容器のボート部分の平面図、第１図ｂは同
断面図、第２図ａ，ｂはそれぞれ焼成容器の蓋の
平面図と断面図、第３図は本発明の製造方法によ
り製造された太陽電池の構造を示す断面図、第４
図は本発明の製造方法により製造された太陽電池
の効果を説明するための分光感度特性の比較図で
ある。
１……焼成容器のボート、２……焼成容器の
蓋、３……蓋の穴、４……ガラス基板、５……
CdS膜、６……CdTe膜、７……カーボン膜、８
……Ag電極、９……Ag−In電極、１０……リー
ド線。
Figure 1a is a plan view of the boat part of the firing container used in the method for producing a sintered film of the present invention, Figure 1b is a sectional view of the same, and Figures 2a and b are plan views of the lid of the firing container, respectively. A cross-sectional view, FIG. 3 is a cross-sectional view showing the structure of a solar cell manufactured by the manufacturing method of the present invention, and FIG.
The figure is a comparison diagram of spectral sensitivity characteristics for explaining the effects of the solar cell manufactured by the manufacturing method of the present invention. 1...Boat of the firing container, 2...Lid of the baking container, 3...Hole in the lid, 4...Glass substrate, 5...
CdS film, 6... CdTe film, 7... Carbon film, 8
...Ag electrode, 9...Ag-In electrode, 10... Lead wire.